Translation - EnglishChapter 3
Potential use of crack propagation laws in fatigue life design
For a given initial defect size, the fatigue life of a structural element can be determined from the integration of a crack propagation law if, on the one hand the crack initiation life is determined by measurements or estimates, and on the other hand if the parameters for the law of propagation are known. The influence of variable amplitude loading can be integrated using the damage accumulation laws. Also, the overload effect that produces plasticity at the crack tip can be integrated to evaluate the consecutive of crack growth retardation effect.
The influence of different parameters on the fatigue resistance of the studied element may be investigated using the calculation of relative fatigue life between two structural elements of the same type.
The analytical formula of fatigue life according to different parameters that influence resistance to fatigue allows probabilistic analysis of the life duration to be made to the extent that some of these parameters are random in nature.
These are the three types of studies that will be approached in the following sections.